diff --git a/include/haproxy/pattern-t.h b/include/haproxy/pattern-t.h
index 477b2bbc6..30ff999b5 100644
--- a/include/haproxy/pattern-t.h
+++ b/include/haproxy/pattern-t.h
@@ -106,6 +106,8 @@ struct pat_ref {
 	struct list head; /* The head of the list of struct pat_ref_elt. */
 	struct list pat; /* The head of the list of struct pattern_expr. */
 	unsigned int flags; /* flags PAT_REF_*. */
+	unsigned int curr_gen; /* current generation number (anything below can be removed) */
+	unsigned int next_gen; /* next generation number (insertions use this one) */
 	int unique_id; /* Each pattern reference have unique id. */
 	unsigned long long revision; /* updated for each update */
 	__decl_thread(HA_SPINLOCK_T lock); /* Lock used to protect pat ref elements */
@@ -122,6 +124,7 @@ struct pat_ref_elt {
 	struct list tree_head; /* all pattern_tree derived from this reference */
 	char *pattern;
 	char *sample;
+	unsigned int gen_id; /* generation of pat_ref this was made for */
 	int line;
 };
 
diff --git a/src/pattern.c b/src/pattern.c
index 7f4f44958..7b4d876e2 100644
--- a/src/pattern.c
+++ b/src/pattern.c
@@ -1756,6 +1756,8 @@ struct pat_ref *pat_ref_newid(int unique_id, const char *display, unsigned int f
 
 	ref->reference = NULL;
 	ref->flags = flags;
+	ref->curr_gen = 0;
+	ref->next_gen = 0;
 	ref->unique_id = unique_id;
 	LIST_INIT(&ref->head);
 	LIST_INIT(&ref->pat);
@@ -1767,7 +1769,8 @@ struct pat_ref *pat_ref_newid(int unique_id, const char *display, unsigned int f
 
 /* This function adds entry to <ref>. It can fail on memory error. It returns
  * the newly added element on success, or NULL on failure. The PATREF_LOCK on
- * <ref> must be held.
+ * <ref> must be held. It sets the newly created pattern's generation number
+ * to the same value as the reference's.
  */
 struct pat_ref_elt *pat_ref_append(struct pat_ref *ref, const char *pattern, const char *sample, int line)
 {
@@ -1777,6 +1780,7 @@ struct pat_ref_elt *pat_ref_append(struct pat_ref *ref, const char *pattern, con
 	if (!elt)
 		goto fail;
 
+	elt->gen_id = ref->curr_gen;
 	elt->line = line;
 
 	elt->pattern = strdup(pattern);